Spatial variation of reference evapotranspiration and its influence on the hydrology of Luvuvhu River Catchment

Abstract

This study estimated spatial variation of reference evapotranspiration (ETo) and its influence on the hydrology of Luvuvhu River Catchment.The ETo plays a key role in irrigation systems design, water resource management under irrigated and rainfed production.Simulation of ETo was performed using the Penman-Monteith method in CROPWAT 8.0 software. Results showed the spatial and temporal distribution of ETo with peaks in summer months. Areas with higher ETo values were near rivers and streams, which generally have more abundant vegetation. Areas with low ETo values were relatively dry, where pasture and grasslands dominated the landscape. Correlation results showed that no relationship exists between streamflow and ETo (r = 0.36) in the study area, hence, a significant relationship exists between rainfall and ETo (r = 0.86). The study recommends the use ofCROPWATmodel for computing ETo under arid and semi-arid climatic conditions for water resource management and planning.